She is told she was abandoned. Only much later would she learn that her family had been a casualty of anti-Asian immigration policy in the United States. Her American father got Congress to pass a special bill that would have allowed her to enter the U.S., yet she went most of her 67 years without knowing that.

"So many coincidences happened in my life," she said in an interview at her house outside Tokyo. "But altogether, you know, I managed to put the whole story, that now I'm settled, and I have peace of mind. Thank goodness that I don't have to live with two people anymore."

Those two people are Mary Ann Vaughn, the girl she was born as, and Marianne Wilson, the girl that fate made her.

Her father, Texas-born James Vaughn, arrived in Japan in early 1946. The 20-year-old civilian was assigned to a U.S. military base in Yokohama. He met 16-year-old Vivienne Wilson working in the PX to help support her family. Their daughter, Mary Ann Vaughn, was born in a Yokohama hospital on April 17, 1949.

It was an ill-fated romance. The military denied Vaughn permission to marry Wilson, based on U.S. immigration law, because she was half-Japanese. Back in the U.S., he wrote to Congress, which passed a law allowing Wilson and her daughter to enter the U.S. It was dated Aug. 5, 1950.

That very day Vivienne Wilson died of tuberculosis. Mary Ann was 16 months old.

Wilson's family asked her nanny to take care of Mary Ann until her father returned. He never did.

She didn't know she was American. In fact, she was taught to be terrified of Americans. But ultimately, an organization set up to help orphans left behind by American soldiers found her.

In letters to the Swedish consul in Tokyo in 1955, the group reported that Mary Ann's nanny wanted to adopt her, but questioned whether that was advisable, given her impoverished circumstances.

Sweden decided it should find a home for her, and a custody battle ensued. The court ruled in Sweden's favor in 1958.

Under a compromise with the Swedish Embassy, the child would go to an international school, live with a foreign host family during the week and stay with her nanny Fumi Yamaguchi on weekends.

That wasn't the only change the deal required. Until then, the girl had been known as Mary Ann Yamaguchi. "From now on," Yamaguchi told her, "your name is going to be Marianne Wilson."

It was a name she hated. Marianne is the Swedish version of Mary Ann, and in her 9-year-old mind, it was the source of all her troubles. She struggled to learn English, and while she met other mixed-race children, it didn't help her understand her own family.

On her deathbed in 1975, Yamaguchi told Marianne everything. James Vaughn was her father, and he hadn't abandoned her, but had tried to find her. She gave her old photos, and said, these are your parents.

Marianne did not investigate further until after she had a family of her own and had become Marianne Wilson Kuroda. Even then it took years to get answers. In 2004, the Japanese Red Cross told her: We found James Vaughn, but unfortunately he died 11 months ago. And you have a younger brother in America.

Three months later, she was flying to Albuquerque, New Mexico.

She and her 56-year-old half-brother, Steve Vaughn, compared photos. They found they had similar ones of their father. They visited the grave of their father, who had died on Feb. 3, 2003, at the age of 77.

"I had to give him respect, you know. But, um, hmm, it was like, you know, 'Why did you die 11 months ago?'" Marianne said. "You could have lived a little bit longer after all these years."

She decided to claim her U.S. citizenship, in his honor. It would take 12 years. U.S. officials had questions about the law, and about why someone who did not intend to move to America wanted citizenship.

"Her case is a consequence of this history of discrimination from immigration law and citizenship law that I thought really needed to be corrected," said Rose Cuison Villazor, a professor at the Immigration Law Clinic at the University of California, Davis, who helped Marianne. "There was ... this awful history that I felt needed to be addressed as a matter of justice."

The U.S. ultimately granted Marianne citizenship. A photo posted this June on Facebook shows a smiling Marianne standing outside the U.S. Embassy in Tokyo, holding up the oath of allegiance she had just signed.

She says she has one more task. She wants to visit the cemetery in the west Texas city of Spur where her paternal grandparents are buried.

"I want to show them my American passport and say, 'Grandpa, Grandma. I'm home.'"